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  • Author or Editor: Charlotte Pratt x
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Abstract

In ‘Concord’ (Vitis labruscana Bailey), a hermaphroditic, self-fertilized, and seeded grape cultivar, the development of pollen and the growth of pollen tubes in the style were adequate for fertilization. Seed formation was limited by 1) the arrested development of many ovules before bloom and 2) the post-bloom dropping of many ovaries containing 1 or more fertilized but retarded ovules. The abscission zone at the base of the pedicel was most distinct during drop. An average of 2 seeds per berry was necessary for berry adherence. Two poorly setting, seeded variants differed quantitatively from ‘Concord’. One had more pre-meiotic ovule abortion and the other more abortion of mature and fertilized ovules. Both had an average of 1 seed per adhering berry. Since they showed neither different chromosome numbers nor transmissible viruses, they were thought to be mutants.

Open Access

Abstract

Range in time and fields and accuracy of references were examined for 100 research papers in HortScience. Referal to the source was difficult or impossible in 31% of the cited articles; 55% of citations contained at least one error.

Open Access

Abstract

Nonsported ‘Rhode Island Greening’ consistently produced its characteristic smooth and symmetrical fruits following ionizing irradiation or vegetative propagation, except for a low incidence of russet-fruited scions in one irradiation experiment. Three russet-fruited sports consistently produced russet fruits after either irradiation or propagation, as in the original limb, but more than half of the scions of another russet sport bore nonrusset fruits following either irradiation or propagation. Two sports with furrowed fruits, when irradiated, pruned severely, disbudded or propagated, produced smooth, symmetrical fruits on 0 - 100% of the scions or branches, with an incidence of 0 - 11% russet-fruited scions in one irradiation experiment. Three sports with russet-furrowed fruits, when irradiated, disbudded or propagated, produced a graduated series of fruits ranging from russet-furrowed to furrowed to smooth and symmetrical, with an incidence of 0 - 8% russet-fruited scions in one irradiation experiment. Another sport with russet-furrowed fruits was stable in limited observations. There was no evidence that variation in fruit type was related to virus infection. The sports are hypothesized to be periclinal chimeras with a mutation for russet in layer I of the apical meristem (unstable sports) or in layers I and II (stable sports), or with a mutation for furrowing in layer III (sports with furrowed fruits) or in layers II and III (sports with russet-furrowed fruits). The appearance of russet fruits in irradiation experiments with nonrusset clones was considered to be the result of new mutation.

Open Access

Abstract

Blushed-fruited sports of striped ‘Northern Spy’ apple (Malus pumila Mill.) are thought to have a mutation for this color pattern in layers I and II of the apical meristem. 1) Increased anthocyanin occurred in the epidermis (derived from L I) and in the hypodermis and outer flesh cells (derived from L II) of mature fruits of 5 sports. 2) One sport crossed with a yellow cultivar produced more blushed- than striped-fruited progeny, indicating that gene(s) for blush were in L II. 3) Three sports consistently produced blushed fruits in the orchard or following gamma irradiation of 3000–5000 rads applied to dormant buds, suggesting that the mutation was in at least the 2 outer layers. Furrowed-fruit mutants were the result of unequal cell size and unsymmetrical growth of the flesh. In 2 of 11 such mutants, anthocyanin was not formed in the depressed area, where the outer cells degenerated.

Open Access

Abstract

Several color sports of ‘Delicious’ and ‘Rome Beauty’ were irradiated with gamma rays as growing trees or as dormant scions. Four sports of ‘Delicious’ and 3 of ‘Rome’ showed radiation-induced reversions in fruit color pattern from blushed to striped or to less red color. Not all cultivars showed spontaneous reversions. Most of the anthocyanin-containing cells producing the red color of the sports occurred in the hypodermis, which was derived from layer II of the apical meristem. The color sports were hypothesized to be periclinal chimeras with a mutation favoring increased anthocyanin in layer II or, by layer reduplication, in both layers II and III. The former chimeras would be more likely to revert than the latter.

Open Access

Abstract

Since the purpose of an index is to retrieve information rapidly, the index must be closely correlated with the objectives of its users (2). An index may deal with general or specialized information. Examples within the field of agriculture range from the computerized Catalog and Index (CAIN, AGRICOLA) for the Bibliography of Agriculture (3) to the table of contents of the Pisum Newsletter. The scope of subject matter is the most important determinant of the method and format of indexing.

Open Access

Abstract

Chromosome counts derived from sectioned buds of 137 apple clones are reported. Of these 128 were determined to be diploid (2n = 34) and 9 to be triploid (2n = 51).

Open Access

Abstract

Widespread stippled browning and premature senescence of leaves of grapevines were observed in grape growing regions near the Great Lakes. Those symptoms were identical to those obtained by exposing 2-year old potted ‘Concord’ and ‘Ives’ grapevines to 30 or 60 pphm ozone (O3) for 6 hr, indicating that the brown leaf disorder of grapevines is oxidant stipple, a manifestation of O3 injury.

Open Access

Abstract

Pale green lethal seedlings of apple (Malus spp.) are characterized by yellowish green color, poor growth of lateral roots, of epicotyl and of leaves, early cessation of apical meristematic activity, and death of the whole plant in about 1 month. Lethal seedlings occur in about 25% of the progeny of 2 heterozygous diploid parents. By this test we determined the homozygosity of 107 diploids (LL) and the heterozygosity of 97 diploids (LI). Among tetraploids 12 were quadriplex (LLLL) and 8 were probably duplex (LLll) or triplex (LLLl), but the expected ratios were not obtained.

Open Access